Paleontologists have finally determined what hyoliths — a group of extinct marine creatures — actually are. Reconstruction of the hyolith Haplophrentis on the Cambrian sea floor. Image credit: D. Dufault / Royal Ontario Museum. Hyoliths evolved over 530 million years ago during the Cambrian period and are among the first animals known to have produced mineralized external skeletons. Long believed to belong to the same family as snails,...
